Better to calculate exact bitrate or use DVD Shrink?

[robertazimmerman]

Hi folks,

May I get opinions, please?

I currently convert all of my AVIs to MPG at maximum bitrate (9,800
kbps). I then create a "DVD" using TMPGEnc DVD Author and then use DVD Shrink to reduce the files so that everything will fit on a single DVD-R.

Would I be better off to determine appropriate bitrates in advance of conversion, so that I don't need to shrink the files? Is there a qualitative difference? Has any one here compared the two methods?

Thanks!

Roberta

[johns0]

Best to calculate the bitrate as close as you can.No need to compare,shrinking will reduce quality if you need to reduce too much.

[SLK001]

Re-encoding always results in superior video.

What's so hard about calculating bitrates?

[bugster]

Always calculate the correct bitrate before hand. There are plenty of simple to use bitrate calculators to choose from. Use VBR for better quality.

[nic2k4]

I thought DVDShrink only changed the bit rate and didn't re-encode, that's why it's so fast.

[Gurm]

No no. DVD Shrink recompresses the transform data. The bitrate is part of the encoding, so there's no way DVD Shrink can touch it. You are producing a horribly wasteful and probably ugly to look at DVD with your method.

[SLK001]

Don't hold back now, Gurm! Tell how you really feel!

[daamon]

Always calculate the correct bitrate before hand. There are plenty of simple to use bitrate calculators to choose from. Use VBR for better quality.

I'll second that. I've always found the VideoHelp Bitrate Calculator good.

[Gurm]

I'm not trying to be mean, I'm just saying... ok lemme try to elaborate.

You're making a HUGE DVD folder. Like 7 Gigs. It's so huge because the bitrate is high. Very little of that 7 Gigs is transform data.

Then you're firing up a transcoder. The bitrate stays high, only you're trying to get a nearly 50% shrink out of the transform data. There just ISN'T enough transform data to work with, I'm amazed that Shrink would even let you make it small enough to fit... and the outcome would likely look TERRIBLE since you're squeezing that transform data so tight.

On the other hand, using the lower bitrate... well, let's be honest - your AVI file didn't have 9800kbps bitrate, did it? Pick a reasonable bitrate to make it fit, and you'll probably find that it's STILL more than enough, and you get to keep all the transform data.

[robertazimmerman]

Well, it certainly looks like there's a concensus!

Thanks!

Roberta

P.S. DVDs compressed using DVD Shrink don't look terrible. I just never bothered to compare "shrunk" ones vs. calculated ones. I just may do that.....